When is fermentation done - measuring with iSpindel

[idserda]

Currently I'm fermenting my third BIAB brew. The previous two brews went okay, but they both seem to be overcarbonated: when I open the bottle, foam very slowly creeps out of it. I kept those in primary for two weeks, three days in secondary and did about two weeks of bottle conditioning. Added about 7 g/liter priming sugar. My hypothesis is that fermentation wasn't completely done when I bottled it, so I'm giving my current brew a bit more time.

My current brew:
- Mashed at 66°C (150F) for 60 minutes, but temperature did drop to 62 °C at the end.
- Batch size: 5 liters
- OG 1.062
- Safale S-04 yeast (pitched half a packet, about 6 grams)
- Fermentation at 20°C (68F)
- Target gravity: 1.012

This has been fermenting for almost three weeks now, but I still see that the gravity my iSpindel is measuring is going down (see attached images). Is fermentation still going on? It's going down very slowly, and also past the target gravity. Would it be safe to transfer this to secondary, add dry hops and bottle it after a few days?

 

[Tall_Yotie]

First:
Do not use a secondary. Do not. That is old process that has been proven to be more bad than good, holds no real benefits. All it does is add an extra spot for infection and oxidation. There is no "secondary" fermentation in beer. So make it simple and keep it in the fermenter all the way through to the end.

4C is a significant drop, but still in the safe mashing range. But that would only affect OG, not fermentation (not significantly at least).

That is a very low FG for your target. It is still fermenting, it drop 1 point in 3 days. That is indeed slow, but still going. There is no harm in letting it go longer, all you are doing is aging it more which will improve flavor.

I would figure that if you dry hopped now, by the time you are done dry hopping (3-7 days depending on your recipe) then fermentation will calm down.

Just don't transfer.

Have you used this device before? Is there a history of creep? Is it properly calibrated? That is a rather linear drop, and I would have expected more of a leveling curve.

 

[idserda]

Thanks for the reply @Tall_Yotie !

First:
Do not use a secondary. Do not. That is old process that has been proven to be more bad than good, holds no real benefits. All it does is add an extra spot for infection and oxidation. There is no "secondary" fermentation in beer. So make it simple and keep it in the fermenter all the way through to the end.

Noted! The book I'm using (Brew by James Morton) mentions this about it:

You can dry hop in your primary fermenter. However, hop oils tend to either float off through the airlock or stick to the walls of yeast, and therefore be dragged down into the trub. If you dry hop in primary, you won't realise the full potential of your hop's aroma. It therefore makes sense to transfer your beer into a secondary fermenter, for dry hopping away from the bulk of your yeast.

But I also saw the lengthy discussions about this here. Guess less work is better, so I'll stick to one fermenter for now. I'm doing the Undead Pale Ale recipe, which seems to be a Three Floyds Zombie Dust clone.

That is a very low FG for your target. It is still fermenting, it drop 1 point in 3 days. That is indeed slow, but still going. There is no harm in letting it go longer, all you are doing is aging it more which will improve flavor.

I would figure that if you dry hopped now, by the time you are done dry hopping (3-7 days depending on your recipe) then fermentation will calm down.

Nice suggestion, I'll let it sit for a bit now then. I'll be gone for a short holiday next week, I'll add the dry hops after that.

If you would use a hydrometer and check the gravity for 3 consecutive days, would you also spot that 1 point drop? Guess that'll be hard right?

Have you used this device before? Is there a history of creep? Is it properly calibrated? That is a rather linear drop, and I would have expected more of a leveling curve.

I've build several iSpindels, two of which I have used myself. Both devices show about the same amount of creep for all three brews I've done, so that's suspicious . They're calibrated using sugar water and a refractometer.

Just checked the fermenter (it's glass), looks like there are some small bubbles stuck to the bottom part of the iSpindel's casing. There's also some small bubbles shooting up from the trub every now and then. Maybe those accumulating bubbles are the cause of the creep?

 

[Tall_Yotie]

Regarding secondary, sure there may be that you lose some good hop oils, and if you really want to transfer then go for it. Just saying that the common "always do it" is super false. I was a pro brewer at a production brewery, and worked with a lot of other pro brewers, and never really saw anyone transfer away trub or move tanks before dry hopping.

Yes, if you check 3 days apart and it is the same, then I would call that done.

For the creep, you may want to do a side-by-side comparison. Make a 1.015 sugar solution and see if you see that creep as well. Or power cycle the unit. Or shake off those bubbles and see what it does. Unfamiliar with the item, though I may look into one myself as I enjoy those types of projects.